This is a request for a computerized new circular dichroism spectrometer. The instrument will be applied principally to research in the following areas: (1) study of the mechanism of interaction between neurophysin and posterior pituitary hormones and of the conformation of posterior pituitary hormones; (2) study of the effects of cations and membrane perturbants on gramicidin channels in membranes; and (3) study of the mechanism of allosteric interactions within E. Coli carbamyl phosphate synthetase.